Winter War

The Winter War was a three-month conflict between the Soviet Union and Finland that occurred from November 1939 to March 1940. The Soviet premier Joseph Stalin feared that Finland would come under German influence as relations between the USSR and Nazi Germany deteriorated, and Stalin proposed trading Soviet lands in southern Karelia for leasing ports at Petsamo and Viipuri and territory on Lake Ladoga and the Gulf of Finland. The Finns refused to agree to ceding this territory, so Stalin sent 700,000 Red Army troops to invade Finland, facing a mere 150,000 troops.

The Leningrad Military District quickly seized Petsamo and cut off the Finns from the Barents Sea, but the Finns conducted a fighting withdrawal to the Mannerheim Line in the south and bloodily repulsed Soviet attacks. The war devolded into stalemate by mid-December, and the poorly-equipped and poorly-led Red Army began to suffer heavy losses due to inadequate supplies, foolhardy attacks, and from frostbite. The Finns counterattacked in late December, and the United Kingdom and France considered sending munitions and troops to support the Finns.

In January 1940, the Soviet general Semyon Timoshenko took command and breached the Mannerheim Line, forcing the Finns back to a second line of defense. When the Finns rejected a second peace agreement (which entailed that the Soviets would return Petsamo to Finland in exchange for territory in the south), the Soviets broke through the second line of defense and attacked Viipuri. On 12 March 1940, a peace treaty was signed, and Finland handed over Karelia and Petsamo to the Soviets, in addition to leasing the Hango Peninsula to the Soviets for 30 years. However, the Soviets had lost 85,000 dead or missing and 186,000 wounded in the deadly war, and they were expelled from the League of Nations.